Shielded tip catheter

ABSTRACT

A multilumen catheter assembly ( 100 ) including an elongated body ( 108 ) having a proximal end ( 102 ) and a distal end ( 104 ) and a first lumen ( 110 ) having a sidewall ( 118 ) extending between the proximal end and the distal end, a first distal opening ( 151 ) disposed at the distal end, and a first guide wire opening ( 152 ) disposed proximally of the distal end and co-planar with the sidewall. The assembly also includes a second lumen ( 112 ) connected to the sidewall and extending from the proximal end toward the distal end, proximally of the distal end. The second lumen ( 112 ) includes a second opening ( 155 ) extending obliquely away from the sidewall distally toward the first distal opening ( 114 ) and a second guide wire opening ( 155 ) disposed proximally of the second opening ( 155 ) and in a plane generally parallel to the sidewall. A method of inserting the catheter into a vessel is also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation application of U.S. patentapplication Ser. No. 10/644,238 filed Aug. 20, 2003 which claimspriority from U.S. Provisional Patent Application Ser. No. 60/405,937filed Aug. 23, 2002.

FIELD OF THE INVENTION

The present invention relates to a multilumen catheter assembly used tosimultaneously withdraw and infuse a fluid to a body, such as duringhemodialysis.

BACKGROUND OF THE INVENTION

Catheters for the introduction or removal of fluids may be placed invarious venous locations and cavities throughout the body forintroduction or removal of these fluids. Such catheterization may beperformed by using a single catheter assembly having multiple lumens. Atypical example of a multiple lumen catheter assembly is a dual lumencatheter in which one lumen introduces fluid and the other lumen removesfluid. Such a multiple lumen catheter assembly is known as the SPLITSTREAM™ catheter, manufactured and sold by Medical Components, Inc. ofHarleysville, Pa.

Generally, to insert any catheter into a blood vessel, the vessel isidentified by aspiration through a long hollow needle in accordance withthe well known Seldinger technique. When blood enters a syringe attachedto the needle, indicating that the vessel has been found, a thin guidewire is then introduced, typically through the puncturing needle orother introducer device into the lumen of the vessel. The introducerdevice is then removed, leaving the guide wire within the vessel. Theguide wire projects beyond the surface of the skin. At this point,several options are available to a physician for catheter placement. Thesimplest is to pass a catheter into the vessel directly over the guidewire. The guide wire is then removed, leaving the catheter in positionwithin the vessel. However, this technique is only possible in caseswhere the catheter is of a relatively small diameter, made of a stiffmaterial, and not significantly larger than the guide wire, for example,for insertion of small diameter dual lumen catheters. If the catheter tobe inserted is significantly larger than the guide wire, a dilatordevice is passed over the guide wire to enlarge the opening into thevessel and then removed. The catheter is then passed over the guidewire, and the guide wire is then removed, leaving the catheter withinthe vessel.

During hemodialysis, the two lumens, the arterial lumen and the venouslumen, are connected to a hemodialysis machine and are used to removetoxic blood from the patient for dialysis and to return dialyzed bloodto the patient, respectively. However, suction of the toxic blood intothe arterial lumen may draw the distal opening of the arterial lumenagainst the wall of the blood vessel into which the lumen is inserted,reducing or cutting off blood flow through the arterial lumen, andsignificantly reducing the amount of blood being dialyzed. Thisreduction in blood flow can lead to a longer dialysis period, or resultin less dialysis of the patient's blood. It would be beneficial toprovide a catheter that reduces the suction of the arterial lumenagainst the blood vessel wall.

Twardowski et al., U.S. Pat. No. 5,405,320 and Davey et al., U.S. Pat.No. 6,280,423 B1 both disclose dual lumen catheters with an arteriallumen that includes an overhanging lip or shield to reduce the suctionof the arterial lumen against the blood vessel wall. However, neitherTwardowski et al. nor Davey et al. disclose a structure or method forinserting the catheter into the blood vessel that minimizes thelikelihood of the overhanging lip snagging on the blood vessel wallduring insertion. It would be beneficial to provide a catheter having anoverhanging lip and a method of inserting the catheter that minimizesthe likelihood of such snagging.

BRIEF SUMMARY OF THE INVENTION

Briefly, the present invention provides a multilumen catheter assembly.The assembly includes an elongated tubular body, divided by a sidewallextending throughout the center of the tube, dividing the tube into twogenerally “D-shaped” lumens, of which the distal openings are at unequallengths. The most distal tip is round and non-tapered with an oval sideopening just proximal to the distal opening to facilitate guide wirepassage. The shorter, more proximal undercut lip lumen has a single ovalside hole opening directly centered just proximal to the center of theundercut (overhanging) lip. The two oval side holes facilitate passageof a guide wire for insertion. The shorter lumen (the arterial oraspiration port) connects through a connecting hub assembly to allowoblique connection of an arterial (generally red color coded) portluer-lock connection tube. The longer lumen (the venous or return port)connection in the hub assembly in a straight-through direction forconnection to the venous (generally blue color coded) luer-lockconnection tube.

Additionally, the present invention provides a method of inserting acatheter assembly over a catheter guide wire. The proximal end of theguide wire is inserted into the tip of the longer (venous return) lumen,out the oval guide wire side hole parallel to the lumen and enters theshorter (arterial aspiration) lumen through the oval guide wire holeinto the lumen of the aspiration port. The guide wire is then advancedthrough the length of the catheter to exit the red luer-lock connector.The catheter is then advanced over the guide wire for percutaneousinsertion without a peel away sheath, thus minimizing the possibility ofbleeding and air embolism. The course of the guide wire through thecatheter tips allows an insertion course co-axial to the guide wire andprovides that the overhanging undercut lip of the shorter port is foldeddown against the longer venous port to prevent difficult passage as thecatheter passes through the venotomy site.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitutepart of this specification, illustrate the presently preferredembodiments of the invention, and, together with the general descriptiongiven above and the detailed description given below, serve to explainthe features of the invention. In the drawings:

FIG. 1 is a side view of a catheter assembly according to a preferredembodiment of the present invention.

FIG. 2 is an enlarged cross sectional view of the catheter lumens shownin FIG. 1, taken along lines 2-2 of FIG. 1.

FIG. 3 is an enlarged cross sectional view of the catheter lumens shownin FIG. 1, taken along lines 3-3 of FIG. 1.

FIG. 4 is an enlarged perspective view of a distal end of the catheterassembly shown in FIG. 1.

FIG. 5 is an enlarged top plan view of the distal end of the catheterassembly shown in FIG. 1.

FIG. 6 is an enlarged side view of the distal end of the catheterassembly shown in FIG. 1.

FIG. 7 is an enlarged side view of the distal end of the catheterassembly shown in FIG. 1, with a guide wire strung through the distalend of the catheter assembly as during insertion of the catheterassembly.

FIG. 8 is an enlarged side view of a distal end of an alternateembodiment of a catheter assembly according to an alternative embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the drawings, like numerals indicate like elements throughout.Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present invention. The words “proximal” and“distal” refer to directions away from and closer to, respectively, theinsertion tip of the catheter according to the present invention. Theterminology includes the words above specifically mentioned, derivativesthereof, and words of similar import. The following describes preferredembodiments of the invention. However, it should be understood based onthis disclosure, that the invention is not limited by the preferredembodiments described herein.

Referring now to FIG. 1, a side view of a catheter assembly 100according to a preferred embodiment of the present invention is shown.The catheter assembly 100 includes a proximal end 102, a distal end 104,and a hub 106 connecting the proximal end 102 and the distal end 104. Anelongated body 108 extends between the hub 106 and the distal end 104.The elongated body 108 is preferably comprised of a first catheter lumen110, also known as a venous lumen and a second catheter lumen 112, alsoknown as an arterial lumen. While only two catheter lumens 110, 112 areshown, those skilled in the art will recognize that the catheterassembly 100 may include more than two lumens 110, 112.

The first lumen 110 extends all of the way between the hub 106 and thedistal end 104 and terminates at the distal end 104 in a first distaltip 114, while the second lumen 112 begins at the hub 106, butterminates prior to the distal end 104 at a second distal tip 116. FIG.2 shows an enlarged sectional view of the first and second lumens 110,112 proximate of the second distal tip 116. A common sidewall 118extends from the hub 106 and terminates at the second distal tip 116.FIG. 3 shows an enlarged sectional view of the first lumen 110 distal ofthe second distal tip 116.

Referring back to FIG. 2, the catheter body 108 preferably has agenerally circular cross section, with the first lumen 110 and thesecond lumen 112 each having a generally “D-shaped” cross section,juxtaposed from each other across the common sidewall 118. Although thecross section of the body 108 is preferably circular, those skilled inthe art will recognize that the cross section of the body 108 may beother shapes, such as oval. It is preferred that the cross section ofthe body 108 be a generally smooth curve to facilitate sealing of thepatient's skin around the body 108 at the incision site, as well as atthe entrance to the vessel, to minimize bleeding. Distal of the seconddistal tip 116, the first lumen 110 preferably has a generally circularcross section.

FIGS. 4, 5, and 6 show an enlarged perspective view, an enlarged topplan view and an enlarged side view, respectively, of the distal end 104of the catheter assembly 100. A transition portion 119 of the firstlumen 110 disposed between the first distal tip and the second distaltip transitions the cross-section of the first lumen 110 from theD-shape shown in FIG. 2 to the generally circular cross section shapeshown in FIG. 3.

Preferably, the body 108 is constructed from a polymer or elastomer,such as CARBOTHANE® polyurethane, with an approximately 20% bariumsulfate/PELLETHANE® polyurethane composition to aid in locating the body108 within the patient's vessel after insertion, such as by ultrasoundand fluoroscopy. However, those skilled in the art will recognize thatother biocompatible materials may be used for the body 108. Preferably,the body 108 has a hardness of approximately 80-A on the Shore durometerscale, although those skilled in the art will recognize that the body108 may be harder or softer.

Referring back to FIG. 1, the hub 106 preferably includes a suture wing120 that extends generally transverse of the body 108. The suture wing120 preferably includes at least one and, more preferably, at least twosuture openings 122 that allow an inserting physician to suture the hub106 to the external skin of the patient into whom the physician hasinserted the catheter assembly 100 to prevent the catheter assembly 100from being dislodged from its inserted position within the patient. Thesuture wing 120 may be fixedly connected to the hub 106, or the suturewing 120 may be rotatably connected to the hub 106, to allow the suturewing 120 to rotate about the hub 106, allowing the inserting physicianadditional flexibility in positioning the hub 106 relative to the skinof the patient.

Preferably, a catheter tissue ingrowth cuff 124 is disposed along anexterior of the body 108 between the second distal tip 116 and the hub106. The catheter tissue ingrowth cuff 124 is used for chronic catheterinsertions, wherein the catheter assembly 100 is intended to be insertedinto the patient for extended periods of time, such as for severalmonths. The catheter tissue ingrowth cuff 124 is disposed within asubcutaneous tunnel according to methods known by those skilled in theart. Preferably, the catheter tissue ingrowth cuff 124 is constructedfrom a generally coarse fabric material, such as a polyester or DACRON®polyester, to enable ingrowing subcutaneous/skin tissue to engage thematerial and secure the catheter ingrowth cuff 124 to thesubcutaneous/skin tissue. For an acute catheterization, the catheterassembly 100 need not be subcutaneously tunneled, and the catheteringrowth cuff 124 may be omitted.

The proximal end 102 of the catheter assembly 100 includes a firstextension tube 130 that fluidly communicates with the first lumen 110 ata distal end 132 of the first extension tube through a first hub conduit133. The first hub conduit 133 transitions from a generally circularcross section at the first extension tube 130 to a generally D-shapedcross section at the first lumen 110. The proximal end 102 of thecatheter assembly 100 also includes a second extension tube 140 thatfluidly communicates with the second lumen 112 at a distal end 142 ofthe second extension tube 140 through a second hub conduit 143. Thesecond hub conduit 143 transitions from a generally circular crosssection at the second extension tube 140 to a generally D-shaped crosssection at the second lumen 112. Preferably, the first extension tube130 extends generally co-axially with the first lumen 110 and the secondextension tube 140 extends at an angle of approximately 20 degreesrelative to the length of the second lumen 112, although those skilledin the art will recognize that the first and second extension tubes 130,140 may extend at other angles as well. Preferably, each of the firstand second extension tubes 130, 140 is constructed from PELLETHANE®polyurethane, although those skilled in the art will recognize thatother material may be used. A proximal end 134 of the first extensiontube 130 preferably terminates at a first connector 136, such as astandard luer lock, as is well known in the art. Preferably, the firstconnector 136 is color coded blue to indicate connection to the venouslumen 110. Also, a proximal end 144 of the second extension tube 140preferably terminates at a second connector 146, such as a standard luerlock. Preferably, the second connector 146 is color coded red toindicate connection to the arterial lumen 112.

A first clamp 138, such as a Roberts clamp is preferably disposed overthe first extension tube 130 between the proximal end 134 and the distalend 132 of the first extension tube 130, and a second clamp 148 ispreferably disposed over the second extension tube 140 between theproximal end 144 and the distal end 142 of the second extension tube140. The first and second clamps 138, 148 serve to releasably secureeach of the first and second extension tubes 130, 140, respectively,preventing fluid flow through each of the first and second extensiontubes 130, 140 when the respective clamp 138, 148 is in the closedposition.

An information ring 139, 149 is disposed within each respective clamp138, 148. An example of such an information ring 139, 149 is disclosedin either of U.S. Pat. No. 6,823,617 or U.S. Design Pat. No. D489,452,which are both owned by the assignee of the present invention, and whichare both incorporated herein by reference in their entireties. Indicia,such as manufacturer's logo, lumen priming volume, warnings, or otherindicia, may be printed on each information ring 139, 149.

Referring back to FIGS. 4-6, the distal end 104 of the catheter assembly100 is now described in more detail. The first lumen 110 preferablyincludes a generally circular first distal opening 151 disposed at thefirst distal tip 114 and a first guide wire opening 152 that is disposedproximally of the first distal tip 114. Preferably, the first guide wireopening 152 is generally oblong or oval in shape, with a major axis ofthe first guide wire opening 152 extending parallel to a major axis ofthe body 108. The first guide wire opening 152 is preferably generallyparallel to a plane of the sidewall 118. Further, the first lumen 110preferably includes at least one and, more preferably, a plurality offirst side ports 154, each being disposed in a plane generallyperpendicular to the plane of the sidewall 118. Preferably, each of theplurality of first side ports 154 is generally circular, although thoseskilled in the art will recognize that the first side ports 154 may beother shapes. Preferably, the first distal tip 114 includes a generallycircular bevel to facilitate a smooth transition between the firstdistal tip 114 and the body of the first lumen 110, and to reduce therisk of the first distal tip 114 snagging the wall of the blood vesselduring insertion.

The second distal tip 116 of the second lumen 112 is generally parabolicin shape and extends obliquely away from the sidewall 118 distallytoward the first distal opening 151. The generally parabolic shape ofthe second distal tip 116 forms an overhanging lip, as seen in FIGS. 1,4, and 6. Referring to FIG. 6 only, preferably, the second distal tip116 of the second lumen 112 extends at an angle β1 of approximately 37.5degrees relative to the plane of the sidewall 118, although thoseskilled in the art will recognize that the angle β1 may be other than37.5 degrees.

Referring to FIGS. 4 and 6, the second distal tip 116 preferablyincludes a second distal opening 155 and a second guide wire opening 156that is disposed proximally of the second distal opening 155.Preferably, the second guide wire opening 156 is generally oblong oroval in shape, with a major axis of the second guide wire opening 156extending parallel to a major axis of the body 108.

The transition portion 119 preferably includes a tapered wall 158 thatangles at an angle β2 of approximately 30 degrees from the plane of thesidewall 118. A cavity 160 is formed between the tapered wall 158 andthe second distal tip 116. The cavity 160 and the oblique shape of thesecond distal tip 116 assist in blood flow into the second lumen 112through the second distal tip opening 155 during hemodialysis, as willbe described in more detail later herein.

To insert the catheter assembly 100 into the patient, an incision isinitially made near an insertion site on the patient's skin, which is tobe aspirated with a syringe or other introducer apparatus near orproximate the area to be catheterized. If the catheter assembly 100 isused for hemodialysis and the area to be catheterized is the internaljugular vein, the incision is made in the clavicular triangle region.The exact location of the incision can be varied by the physician. Inaccordance with the Seldinger technique, a hollow needle is insertedthrough the incision and into the vein, and the vein is then aspirated.A guide wire is then passed through the needle and the needle isremoved. Next, after dilating the soft tissue track and venatory site,the catheter assembly 100 is inserted over the guide wire. Thisinsertion technique eliminates the need for a sheath to be inserted overthe guide wire, greatly reducing the risk of air embolism.

Prior to insertion of the catheter assembly 100 into the patient, thecatheter assembly 100 of FIG. 1 is inserted over the proximal end of theguide wire as follows. A proximal end 162 of a guide wire 160, shown inFIG. 7, is inserted into the first distal opening 151 and pushed throughthe first lumen 110 to the first guide wire opening 152. The proximalend 162 of the guide wire 160 is then pushed through the first guidewire opening 152, so that the proximal end 162 of the guide wire 160exits the catheter body 108. The proximal end 162 of the guide wire 160is next pulled longitudinally along the exterior of the first lumen 110and over the second distal tip 116 to the second guide wire opening 156,where the proximal end 162 of the guide wire 160 is inserted through thesecond guide wire opening 156 and into the second lumen 112. Theproximal end 162 of the guide wire 160 is inserted through the secondlumen 112 and pushed through the second lumen 112 until the proximal end162 of the guide wire 160 exits the catheter assembly 100.

As the guide wire 160 is pulled through both the first guide wireopening 152 and the second guide wire opening 156, the guide wire 160between the first guide wire opening 152 and the second guide wireopening 156 engages the second distal tip 116 and directs the seconddistal tip 116 into the cavity 160, as shown in FIG. 7. With the seconddistal tip 116 in this position, the distal end 104 of the catheterassembly 100 may be inserted into the vessel more directly, preventingthe second distal tip 116 from catching on the wall of the blood vesseland potentially snagging on the wall of the vessel. The distal end 104of the catheter assembly 100 is inserted as far into the vessel asdesired by the physician, and as confirmed by fluoroscopy. When thedistal end 104 of the catheter 100 is in its desired position, the guidewire 160 is pulled through the proximal end 102 of the catheter assembly100 and removed. Next, the incision is closed and the hub 106 is securedto the external skin of the patient by suturing the suture wing 120 tothe skin. The open of first and second connectors 136, 146 are connectedin fluid communication to respective fluid inlets and outlets of ahemodialysis unit (not shown), or other fluid transfer equipment (notshown) and dialysis may now begin.

In use, after the dialysis machine is connected to the catheter assembly100 and turned on, the dialysis machine draws blood from the vesselthrough the second lumen 112. In the event that the pressure drop in thevessel caused by the blood being drawn into the second lumen 112 forcesthe wall of the vessel toward the second distal opening 155, theoverhanging lip of the second distal tip 116 prevents the vessel wallfrom totally occluding the second distal opening 155 and shutting offblood flow through the second lumen 112.

The blood drawn into the second lumen 112 flows to the hemodialysismachine where the blood is cleaned and processed. The blood is thenpumped through the first lumen 110 for discharge back into the vessel.The first distal opening 151 and the first side ports 154 providedischarge ports for the blood to be discharged from the first lumen 110.

A distal end 204 of an alternate embodiment of a catheter assembly 200having an alternate first distal tip 214 is shown in FIG. 8. Instead ofa plurality of generally circular side ports 154 as shown in the firstdistal tip 114 of the embodiment in FIG. 4, the alternate first distaltip 214 includes a plurality of side ports 254 that are each generallysemi-circular and end at the most distal portion of the first distal tip214, merging with the first distal opening 251.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

1. A multilumen catheter assembly comprising: an elongated body having aproximal end and a distal end; a first lumen extending between theproximal end and the distal end, and having a first distal openingdisposed at the distal end; a second lumen and extending between theproximal end and a second distal end, proximal of the distal end, asidewall extending between the proximal end and the distal end andseparating the first and second lumens, wherein the second lumenincludes a second opening extending obliquely away from the sidewalldistally toward the first opening; and wherein the second distal endconcludes in a tip section that is undercut along the sidewall from afirst side of the elongated body to a second, opposite side thereof toform an overhanging lip, thereby facilitating prevention of occlusion ofthe second opening by the vessel wall.
 2. The multilumen catheterassembly according to claim 1, wherein the undercut beneath the seconddistal end tip section is elongated.
 3. The multilumen catheter assemblyaccording to claim 1, wherein the second distal end tip section iselongated to enable deflection toward the first lumen during patientinsertion.
 4. The multilumen catheter assembly according to claim 3,wherein the second distal end tip section is tapered and includes asidewall portion facing away from the first lumen that is angledslightly distally.
 5. The multilumen catheter assembly according toclaim 3, wherein the first lumen, distally of the second lumen distaltip section, includes a transition portion that transitions thecross-section of the first lumen from a generally noncircular crosssection shape to a generally circular cross section shape, and includesa tapered wall angled slightly proximally toward the second lumen distaltip section.
 6. The multilumen catheter assembly according to claim 1,wherein the first lumen and the second lumen each have a cross-sectionalarea sufficiently large in cross-sectional area for blood transmissiontherethrough.
 7. The multilumen catheter assembly according to claim 1,wherein at least the second lumen has a cross section that is D-shaped.